In the drilling and completion arts, many different uses of flapper valves are made. These valves are failsafe and robust and hence have been adopted by individual operators and regulatory agencies alike for use in downhole industries. Flappers of flapper valves are generally articulated to a housing in one portion thereof and allowed to swing relatively freely otherwise. Such flappers may be of a number of shapes including square, round, etc. and in the downhole industry are often rounded as tubing strings used in this industry tend to be at least substantially cylindrical.
Flappers are commonly openable hydraulically either by the application of hydraulic pressure through a control line forcing a flow tube to push the flapper open or in the case of an injection valve, applied fluid pressure acting directly upon the flapper. While these configurations work well for their intended purposes, improvements in functionality and/or cost reduction are always welcomed by the art.